在鼠标悬停上设置状态栏文本 - 适用于控件，但不适用于MenuItems [英] Set Statusbar Text on Mouse Hover - Works for controls but not MenuItems

问题描述

我设计了下面的代码，用于在mouseover上显示控件的Tag属性。该代码适用于标准和TextBoxes等标准控件，但我无法让它适用于我的MenuItems（更具体地说是ToolStripMenuItems）。你们可否请看看我的代码，并告诉我我做错了什么？

  public void Form1_Load（object sender，EventArgs e）
  

{

...

this.addEventsToAllComponents（this）;

}

  private void addEventsToAllComponents（Component component）
 {
 if（component is MenuItem）
 {
 MenuItem menuItem = component as MenuItem; 
 menuItem.Select + = new EventHandler（menuItem_Select）; 
} 
 else if（component is Control）
 {
 Control ctrl = component as Control; 
 foreach（ctrl.Controls中的控件控件）
 {
 control.MouseEnter + = new EventHandler（this.control_MouseEnter）; 
 control.MouseLeave + = new EventHandler（this.control_MouseLeave）; 
 if（control.HasChildren）
 addEventsToAllComponents（control）; 
 
 
 
 $ b private void menuItem_Select（object sender，EventArgs e）
 {
 MenuItem menuItem = sender as MenuItem; 
 
 if（menuItem.Tag.ToString（）。Length> 0）
 this.toolStripStatusLabel1.Text = menuItem.Tag.ToString（）; 
} 
 
 private void control_MouseEnter（object sender，EventArgs e）
 {
 Control control = sender as Control; 
 
 if（control.Tag.ToString（）。Length> 0）
 this.toolStripStatusLabel1.Text = control.Tag.ToString（）; 
} 
 
 private void control_MouseLeave（object sender，EventArgs e）
 {
 if（this.toolStripStatusLabel1.Text.ToString（）。Length> 0）
 this.toolStripStatusLabel1.Text =; 
} 
  

解决方案

你的代码。

1st。 MenuStrip的Items不是Item的子项，所以HasChildren将返回false。相反，它们位于MenuStrip的Items集合中。你需要特别处理一个MenuStrip事件。
在下面的AddEvents ...方法中添加以下代码：

 （snip ...）
 //旧代码
 if（control.HasChildren）
 AddEventsToAllControls（control）; 
 //在
下面添加新的代码if（control为MenuStrip）{
 MenuStrip ms =控制为MenuStrip; 
 AddEventsToAllToolStripMenuitems（ms.Items）; 
} 
  

并添加新方法如下：

  private void AddEventsToAllToolStripMenuitems（ToolStripItemCollection items）{
 foreach（ToolStripItem tsi in items）{
 tsi.MouseEnter + = new EventHandler（this。 control_MouseEnter）; 
 tsi.MouseLeave + = new EventHandler（this.control_MouseLeave）; 
 if（tsi是ToolStripMenuItem）{
 ToolStripMenuItem mi = tsi作为ToolStripMenuItem; 
 AddEventsToAllToolStripMenuitems（mi.DropDownItems）; 
} 
} 
} 
  

第二。 ToolStripItem不是从Control派生的，所以在MouseEnter中， sender作为Control 语句将失败（控件将为null）。做这样的事情：

  Control control = sender as Control; 
 if（control！= null&&& control.Tag！= null&&&& control.Tag.ToString（）。Length> 0）
 this.toolStripStatusLabel1.Text = control.Tag的ToString（）; 
 
 ToolStripItem tsi = sender as ToolStripItem; 
 if（tsi！= null&& tsi.Tag！= null&& tsi.Tag.ToString（）。Length> 0）
 this.toolStripStatusLabel1.Text = tsi.Tag的ToString（）; 
  

（我也添加了一些空的检查）

<这应该会让你走。

I devised the following code for displaying a control's Tag property on mouseover. The code works fine for standard controls such as Labels and TextBoxes but I cannot get it to work for my MenuItems (more specifically ToolStripMenuItems). Could y'all please take a look at my code and tell me what I did wrong? Thanks in advance!

public void Form1_Load(object sender, EventArgs e)

{

...

this.addEventsToAllComponents(this);

}

    private void addEventsToAllComponents(Component component)
{
  if (component is MenuItem)
  {
    MenuItem menuItem = component as MenuItem;
    menuItem.Select += new EventHandler(menuItem_Select);
  }
  else if (component is Control)
  {
    Control ctrl = component as Control;
    foreach (Control control in ctrl.Controls)
    {
      control.MouseEnter += new EventHandler(this.control_MouseEnter);
      control.MouseLeave += new EventHandler(this.control_MouseLeave);
      if (control.HasChildren)
        addEventsToAllComponents(control);
    }
  }
}

    private void menuItem_Select(object sender, EventArgs e)
{
  MenuItem menuItem = sender as MenuItem;

  if (menuItem.Tag.ToString().Length > 0)
    this.toolStripStatusLabel1.Text = menuItem.Tag.ToString();
}

private void control_MouseEnter(object sender, EventArgs e)
{
  Control control = sender as Control;

  if (control.Tag.ToString().Length > 0)
    this.toolStripStatusLabel1.Text = control.Tag.ToString();
}

private void control_MouseLeave(object sender, EventArgs e)
{
  if (this.toolStripStatusLabel1.Text.ToString().Length > 0)
    this.toolStripStatusLabel1.Text = "";
}

解决方案

There are a few problems with your code.

1st. The Items of a MenuStrip are not children of the Item, so HasChildren will return false. Instead, they are in the Items collection of the MenuStrip. You need to handle a MenuStrip occurrence specially. Add the following code in your AddEvents... method below:

(snip...)
// old code                    
if (control.HasChildren)
    AddEventsToAllControls(control);
//add new code below
if (control is MenuStrip) {
    MenuStrip ms = control as MenuStrip;
    AddEventsToAllToolStripMenuitems(ms.Items);
}

And add the new method as follows:

private void AddEventsToAllToolStripMenuitems (ToolStripItemCollection items) {
    foreach (ToolStripItem tsi in items) {
        tsi.MouseEnter += new EventHandler(this.control_MouseEnter);
        tsi.MouseLeave += new EventHandler(this.control_MouseLeave);
        if (tsi is ToolStripMenuItem) {
            ToolStripMenuItem mi = tsi as ToolStripMenuItem;
            AddEventsToAllToolStripMenuitems(mi.DropDownItems);
        }
    }
}

2nd. ToolStripItem doesn't derive from Control, so in MouseEnter the sender as Control statement will fail (control will be null). Do something like this:

Control control = sender as Control;
if (control != null && control.Tag != null && control.Tag.ToString().Length > 0)
    this.toolStripStatusLabel1.Text = control.Tag.ToString();

ToolStripItem tsi = sender as ToolStripItem;
if (tsi != null && tsi.Tag != null && tsi.Tag.ToString().Length > 0)
    this.toolStripStatusLabel1.Text = tsi.Tag.ToString();

(I also added some null checks)

This should get you going.

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